update
This commit is contained in:
prod2
parent
70fa10bfa6
commit
c21c797ef4
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@ -0,0 +1,116 @@
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import strformat
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import strutils
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import value
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type
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OpCode* = enum
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opReturn, opCall, # functions
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opPop, # pop
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opPrint, # print
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opNegate, opNot # unary
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opAdd, opSubtract, opMultiply, opDivide, # math
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opEqual, opGreater, opLess, # comparison
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opTrue, opFalse, opNil, # literal
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opConstant, # constant
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opDefineGlobal, opGetGlobal, opSetGlobal, # globals (uses constants)
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opGetLocal, opSetLocal, # locals
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opJumpIfFalse, opJump, opLoop, opJumpIfFalsePop, # jumps
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Chunk* = object
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code*: seq[uint8]
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constants*: seq[KonValue]
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lines*: seq[int]
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name*: string # name of the module/chunk/files
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DoubleUint8* = array[2, uint8]
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const argSize* = 2
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const argMax*: int = 256*256
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proc initChunk*(name: string): Chunk =
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Chunk(code: @[], name: name, lines: @[], constants: @[])
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proc writeChunk*(ch: var Chunk, code: uint8, line: int) =
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ch.code.add(code)
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ch.lines.add(line)
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proc writeChunk*(ch: var Chunk, code: OpCode, line: int) =
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ch.code.add(code.uint8)
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ch.lines.add(line)
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proc writeChunk*(ch: var Chunk, code: DoubleUint8, line: int) =
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for c in code:
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ch.code.add(c)
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ch.lines.add(line)
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proc len*(ch: Chunk): int =
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ch.code.len
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proc toDU8*(integ: int): DoubleUint8 =
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cast[ptr array[2, uint8]](integ.unsafeAddr)[]
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proc toInt*(du8: DoubleUint8): int =
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cast[uint16](du8).int
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proc DU8ptrToInt*(du8: ptr uint8): int =
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cast[ptr uint16](du8)[].int
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proc addConstant*(ch: var Chunk, constant: KonValue): int =
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ch.constants.add(constant)
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ch.constants.high
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proc writeConstant*(ch: var Chunk, constant: KonValue, line: int): int =
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result = ch.addConstant(constant)
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ch.writeChunk(opConstant, line)
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ch.writeChunk(result.toDU8, line)
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const simpleInstructions = {
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opReturn,
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opPop,
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opPrint,
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opNegate, opNot,
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opAdd, opSubtract, opMultiply, opDivide,
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opEqual, opGreater, opLess,
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opTrue, opFalse, opNil
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}
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const constantInstructions = {
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opConstant,
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opDefineGlobal, opGetGlobal, opSetGlobal,
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}
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const argInstructions = {
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opCall,
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opGetLocal, opSetLocal,
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opJumpIfFalse, opJump, opLoop, opJumpIfFalsePop,
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}
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proc disassembleChunk*(ch: Chunk) =
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echo &"== Chunk {ch.name} begin =="
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echo "index line instruction"
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var c: int = 0
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var lastLine = -1
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while c < ch.code.len:
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template instruction: uint8 = ch.code[c]
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template line: int = ch.lines[c]
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template double: DoubleUint8 = [ch.code[c+1], ch.code[c+2]]
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let cFmt = &"{c:04}"
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let lineFmt = if lastLine == line: " | " else: &"{line:04}"
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try:
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write stdout, &"[{cFmt}] {lineFmt} {instruction.OpCode} ({instruction.toHex(2)}"
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case instruction.OpCode:
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of simpleInstructions:
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write stdout, ")\n"
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of argInstructions:
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write stdout, &" {double[0].toHex(2)} {double[1].toHex(2)})\n"
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c += 2
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of constantInstructions:
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let i = double.toInt
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write stdout, &" {double[0].toHex(2)} {double[1].toHex(2)})\n"
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echo &" points to constant {ch.constants[i]} (i: {i})"
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c += 2
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except:
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echo &"[{cFmt}] {lineFmt} Unknown opcode {instruction}"
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c.inc
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echo &"== Chunk {ch.name} end =="
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@ -0,0 +1,762 @@
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import strformat
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import strutils
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import sugar
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import tables
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import options
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import scanner
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import chunk
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import value
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import config
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type
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Local = object
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name: string # name of this local
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index: int # what is its index in the stack (0 is the stack bottom - nil in the main function)
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depth: int # depth of this local
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# if depth is -1, the variable cannot be referenced yet
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# its depth will be set once its first ever value is determined
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Scope = ref object
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labels: seq[string]
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#depth: int
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goalStackIndex: int # the stack count it started with plus 1
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jumps: seq[int] # jumps to be patched that jump to the end
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function: bool # if true, it is a function
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Compiler = ref object
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#
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# input
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#
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scanner: Scanner
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source: string
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#
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# state
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#
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previous: Token
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current: Token
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canAssign: bool
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locals: seq[Local]
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scopes: seq[Scope]
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stackIndex: int # how large the stack is
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# when there's an error both are set
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# panic mode can be turned off e.g. at block boundaries
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panicMode: bool
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#
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# output
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#
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chunk*: Chunk
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hadError*: bool
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Precedence = enum
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pcNone, pcAssignment, pcOr, pcAnd, pcEquality, pcComparison,
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pcTerm, pcFactor, pcUnary, pcCall, pcPrimary
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# pcUnary applies to all prefix operators regardless of this enum's value
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# changing pcUnary's position can change the priority of all unary ops
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#
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# Note: unary only rules should have precedence pcNone!!!
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ParseRule = object
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name: string # debug purposes only
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prefix: (Compiler) -> void
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infix: (Compiler) -> void
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prec: Precedence # only relevant to infix, prefix always has pcUnary
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proc newScope(comp: Compiler, function: bool): Scope =
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result.new()
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#result.depth = comp.scopes.len + 1
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result.function = function
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result.goalStackIndex = comp.stackIndex + 1
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comp.scopes.add(result)
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# HELPERS FOR THE COMPILER TYPE
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proc newCompiler*(name: string, source: string): Compiler =
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result = new(Compiler)
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result.chunk = initChunk(name)
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result.source = source
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result.hadError = false
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result.panicMode = false
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result.canAssign = true
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result.locals = @[]
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result.scopes = @[]
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proc errorAt(comp: Compiler, line: int, msg: string, at: string = "") =
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if comp.panicMode:
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return
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write stderr, &"[line {line}] Error "
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if at.len > 0:
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write stderr, &"at {at} "
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write stderr, msg
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write stderr, "\n"
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comp.hadError = true
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comp.panicMode = true
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proc error(comp: Compiler, msg: string) =
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## create a simple error message
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comp.errorAt(comp.previous.line, msg)
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proc errorAtCurrent(comp: Compiler, msg: string) =
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comp.errorAt(comp.current.line, msg)
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proc advance(comp: Compiler) =
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comp.previous = comp.current
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while true:
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comp.current = comp.scanner.scanToken()
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when debugScanner:
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comp.current.debugPrint()
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if (comp.current.tokenType != tkError):
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break
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comp.errorAtCurrent(comp.current.text)
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proc match(comp: Compiler, tokenType: TokenType): bool =
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if comp.current.tokenType == tokenType:
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comp.advance()
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true
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else:
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false
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proc consume(comp: Compiler, tokenType: TokenType, msg: string) =
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if comp.current.tokenType == tokenType:
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comp.advance()
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else:
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comp.errorAtCurrent(msg)
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proc synchronize(comp: Compiler) =
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comp.panicMode = false
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while comp.current.tokenType != tkEof:
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if comp.previous.tokenType in {tkSemicolon, tkRightBrace}:
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return
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if comp.current.tokenType in {tkFunct, tkVar, tkFor, tkIf, tkWhile}:
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return
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comp.advance()
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proc writeChunk(comp: Compiler, dStackIndex: int, ch: OpCode | DoubleUint8) =
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comp.stackIndex += dStackIndex
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when debugCompiler:
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debugEcho &"new stackindex: {comp.stackIndex}, delta: {dStackIndex} due to {ch.repr}"
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comp.chunk.writeChunk(ch, comp.previous.line)
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proc writeConstant(comp: Compiler, constant: KonValue) =
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comp.stackIndex.inc
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let index = comp.chunk.writeConstant(constant, comp.previous.line)
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if index >= argMax:
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comp.error("Too many constants in one chunk.")
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proc addLocal(comp: Compiler, name: string, delta: int) =
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if comp.locals.len >= argMax:
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comp.error("Too many local variables in function.")
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# if delta is 0 or negative, it means that it is already on the stack when addLocal is called
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# if delta is positive, the first ever value of the local is to the right
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comp.locals.add(Local(name: name, depth: if delta > 0: -1 else: comp.scopes.high, index: comp.stackIndex + delta))
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proc markInitialized(comp: Compiler) =
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comp.locals[comp.locals.high].depth = comp.scopes.high
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# PARSE RULE/PRECEDENCE MISC
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proc nop(comp: Compiler) = discard
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var rules: Table[TokenType, ParseRule]
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template genRule(ttype: TokenType, tprefix: (Compiler) -> void, tinfix: (Compiler) -> void, tprec: Precedence) =
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if tprec == pcUnary:
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raise newException(Exception, "pcUnary cannot be used as a rule precedence! Use pcNone for unary-only rules!")
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elif tprec == pcPrimary:
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raise newException(Exception, "Invalid rule: pcPrimary cannot be used for binary operators, if this rule is for a primary value, use pcNone!")
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elif tprec == pcNone and tinfix != nop:
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raise newException(Exception, "Invalid rule: pcNone only allowed for unary operators and primary values, not for infix ones!")
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rules[ttype] = ParseRule(name: $ttype, prefix: tprefix, infix: tinfix, prec: tprec)
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proc getRule(opType: TokenType): Option[ParseRule] =
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if rules.hasKey(opType):
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some(rules[opType])
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else:
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none(ParseRule)
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proc applyRule(rule: ParseRule): Precedence =
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# returns the rule's precedence
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rule.prec
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proc increment(prec: Precedence): Precedence =
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# increases precedence by one
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if prec == pcPrimary:
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raise newException(Exception, "Invalid ruletable, pcPrimary precedence increment attempted.")
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else:
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Precedence(int(prec) + 1)
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proc `<=`(a, b: Precedence): bool =
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int(a) <= int(b)
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# JUMP HELPERS
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proc emitJump(comp: Compiler, delta: int, op: OpCode): int =
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# delta -> 0 if the jump does not pop
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# delta -> -1 if the jump pops the condition from the stack
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comp.writeChunk(delta, op)
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comp.writeChunk(0, 0xffffff.toDU8)
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comp.chunk.len - argSize
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proc patchJump(comp: Compiler, offset: int) =
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let jump = (comp.chunk.len - offset - argSize)
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if (jump > argMax):
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comp.error("Too much code to jump over.")
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let jumpt = jump.toDU8
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comp.chunk.code[offset] = jumpt[0]
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comp.chunk.code[offset + 1] = jumpt[1]
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proc emitLoop(comp: Compiler, loopstart: int, delta: int, op: OpCode) =
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comp.writeChunk(delta, op)
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let offset = comp.chunk.len - loopstart + argSize
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if offset > argMax:
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comp.error("Loop body too large.")
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comp.writeChunk(0, offset.toDU8)
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# SCOPE HELPERS
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proc beginScope(comp: Compiler, function: bool = false) =
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let scope = comp.newScope(function)
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when debugCompiler:
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debugEcho &"Begin scope called for depth {comp.scopes.len} function? {function}"
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if function:
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scope.labels.add("result")
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else:
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while comp.match(tkLabel):
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let label = comp.previous.text[1..^1]
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scope.labels.add(label)
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if function:
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# if it's a function scope, the frame will move
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# access to outside locals is also limited to upvalues and closures
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comp.stackIndex = 0
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else:
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# only put the opNil if it's not a function scope, since
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# function scopes are initialized by the caller
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comp.writeChunk(1, opNil)
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comp.addLocal("^", delta = 0)
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# note, that later added scope labels will not be accessible through ^
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# so it is better not to assign scope labels after beginScope
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for label in scope.labels:
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comp.addLocal(&"^{label}", delta = 0)
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proc restore(comp: Compiler, scope: Scope) =
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let delta = comp.stackIndex - scope.goalStackIndex
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for i in countup(1, delta):
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comp.writeChunk(-1, opPop)
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when assertionsCompiler:
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if not comp.stackIndex == scope.goalStackIndex:
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comp.error("Assertion failed in restore")
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when debugCompiler:
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debugEcho &"Restored scope: delta {delta}"
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proc restoreInFunct(comp: Compiler, scope: Scope) =
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when debugCompiler:
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var pops = 0
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while comp.stackIndex > 0:
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comp.writeChunk(-1, opPop)
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when debugCompiler:
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inc pops
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when assertionsCompiler:
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if not comp.stackIndex == 0:
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comp.error("Assertion failed in restoreInFunct")
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comp.stackIndex = scope.goalStackIndex
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when debugCompiler:
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debugEcho &"Restored function scope: delta {pops}; new stackindex: {comp.stackIndex}"
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proc jumpToEnd(comp: Compiler, scope: Scope) =
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let delta = comp.stackIndex - scope.goalStackIndex
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for i in countup(1, delta):
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comp.writeChunk(0, opPop)
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let jmp = comp.emitJump(0, opJump)
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||||
scope.jumps.add(jmp)
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||||
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||||
proc endScope(comp: Compiler) =
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# remove locals
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||||
let popped = comp.scopes.pop()
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||||
let function = popped.function
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||||
when debugCompiler:
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||||
debugEcho &"End scope called for depth {comp.scopes.len} function? {function}"
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||||
if function:
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||||
comp.restoreInFunct(popped)
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||||
else:
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comp.restore(popped)
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||||
# patch jumps to after the scope (such jumps from breaks emit the pops before jumping)
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for jump in popped.jumps:
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comp.patchJump(jump)
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if function:
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comp.writeChunk(0, opReturn)
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||||
|
||||
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||||
# EXPRESSIONS
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||||
proc parsePrecedence(comp: Compiler, prec: Precedence) =
|
||||
comp.advance()
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||||
let rule = comp.previous.tokenType.getRule
|
||||
|
||||
if rule.isSome and rule.get.prefix != nop:
|
||||
comp.canAssign = prec <= pcAssignment
|
||||
|
||||
let rule = rule.get
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||||
when debugCompiler:
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||||
debugEcho &"parsePrecedence call, valid prefix op found, rule used: {rule.name}, precedence: {prec}"
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||||
|
||||
rule.prefix(comp)
|
||||
|
||||
while comp.current.tokenType.getRule.isSome and
|
||||
prec <= comp.current.tokenType.getRule.get.prec:
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||||
comp.advance()
|
||||
# checked for isSome in the loop
|
||||
# since advance moves current to previous
|
||||
if comp.previous.tokenType.getRule.get.infix == nop:
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||||
# should never happen, as having a precedence set
|
||||
# means that it is a binary op
|
||||
comp.error("Invalid rule table.")
|
||||
return
|
||||
else:
|
||||
let infixRule = comp.previous.tokenType.getRule.get.infix
|
||||
infixRule(comp)
|
||||
else:
|
||||
comp.error("Expect expression.")
|
||||
|
||||
proc expression(comp: Compiler) =
|
||||
## The lowest precedence among the pratt-parsed expressions
|
||||
|
||||
# DO NOT ADD ANYTHING HERE
|
||||
# only use the pratt table for parsing expressions!
|
||||
when assertionsVM:
|
||||
let oldStackIndex = comp.stackIndex
|
||||
comp.parsePrecedence(pcAssignment)
|
||||
when assertionsVM:
|
||||
let diff = comp.stackIndex - oldStackIndex
|
||||
if diff != 1:
|
||||
comp.error(&"Assertion failed: expression increased ({oldStackIndex} -> {comp.stackIndex}) the stack index by {diff} (should be 1).")
|
||||
|
||||
|
||||
proc number(comp: Compiler) =
|
||||
# assume the number is already advanced through
|
||||
let value = comp.previous.text.parseFloat.toKonValue
|
||||
comp.writeConstant(value)
|
||||
when debugCompiler:
|
||||
debugEcho &"Written constant (type: {value.konType}, str repr: {$value}) to chunk"
|
||||
|
||||
tkNumber.genRule(number, nop, pcNone)
|
||||
|
||||
proc expFalse(comp: Compiler) =
|
||||
comp.writeChunk(1, opFalse)
|
||||
|
||||
tkFalse.genRule(expFalse, nop, pcNone)
|
||||
|
||||
proc expTrue(comp: Compiler) =
|
||||
comp.writeChunk(1, opTrue)
|
||||
|
||||
tkTrue.genRule(expTrue, nop, pcNone)
|
||||
|
||||
proc expNil(comp: Compiler) =
|
||||
comp.writeChunk(1, opNil)
|
||||
|
||||
tkNil.genRule(expNil, nop, pcNone)
|
||||
|
||||
proc expString(comp: Compiler) =
|
||||
let value = comp.previous.text[1..^2].toKonValue()
|
||||
comp.writeConstant(value)
|
||||
when debugCompiler:
|
||||
debugEcho &"Written constant (type: {value.konType}, str repr: {$value}) to chunk"
|
||||
|
||||
tkString.genRule(expString, nop, pcNone)
|
||||
|
||||
proc resolveLocal(comp: Compiler, name: string): int =
|
||||
## returns the stack index of the local of the name
|
||||
var i = comp.locals.high
|
||||
while i >= 0:
|
||||
let local = comp.locals[i]
|
||||
if local.name == name:
|
||||
if local.depth == -1:
|
||||
comp.error("Can't read local variable in its own initializer.")
|
||||
return local.index
|
||||
i.dec
|
||||
return -1
|
||||
|
||||
proc variable(comp: Compiler) =
|
||||
# named variable
|
||||
var getOp = opGetGlobal
|
||||
var setOp = opSetGlobal
|
||||
|
||||
let name = comp.previous.text
|
||||
|
||||
# try resolving local, set arg to the index on the stack
|
||||
var arg = comp.resolveLocal(name)
|
||||
|
||||
if arg != -1:
|
||||
# local
|
||||
getOp = opGetLocal
|
||||
setOp = opSetLocal
|
||||
else:
|
||||
# global
|
||||
arg = comp.chunk.addConstant(name.toKonValue)
|
||||
|
||||
if comp.match(tkEqual):
|
||||
# assignment (global/local)
|
||||
if not comp.canAssign:
|
||||
comp.error("Invalid assignment target.")
|
||||
return
|
||||
comp.expression()
|
||||
comp.writeChunk(0, setOp)
|
||||
else:
|
||||
# get (global/local)
|
||||
comp.writeChunk(1, getOp)
|
||||
|
||||
comp.writeChunk(0, arg.toDU8)
|
||||
|
||||
tkIdentifier.genRule(variable, nop, pcNone)
|
||||
|
||||
proc grouping(comp: Compiler) =
|
||||
# assume initial '(' is already consumed
|
||||
comp.expression()
|
||||
comp.consume(tkRightParen, "Expect ')' after expression.")
|
||||
|
||||
|
||||
proc parseCall(comp: Compiler) =
|
||||
# ( consumed
|
||||
|
||||
# create the call env
|
||||
# current stack before opCall:
|
||||
# ... <funct obj> <arg1> <arg2> <arg3>
|
||||
# opCall converts it to this
|
||||
# ... <ret val> <arg1> <arg2> <arg3>
|
||||
|
||||
var argcount = 0
|
||||
# put args on stack
|
||||
while comp.current.tokenType notin {tkRightParen, tkEof}:
|
||||
comp.expression()
|
||||
inc argcount
|
||||
if comp.current.tokenType != tkRightParen:
|
||||
comp.consume(tkComma, "Expected ',' between arguments in function calls.")
|
||||
comp.consume(tkRightParen, "Expected ')' after arguments in function calls.")
|
||||
|
||||
# emit call
|
||||
comp.writeChunk(-argcount, opCall)
|
||||
comp.writeChunk(0, argcount.toDU8)
|
||||
|
||||
|
||||
tkLeftParen.genRule(grouping, parseCall, pcCall)
|
||||
|
||||
proc unary(comp: Compiler) =
|
||||
let opType = comp.previous.tokenType
|
||||
|
||||
comp.parsePrecedence(pcUnary)
|
||||
|
||||
case opType:
|
||||
of tkMinus:
|
||||
comp.writeChunk(0, opNegate)
|
||||
of tkBang:
|
||||
comp.writeChunk(0, opNot)
|
||||
else:
|
||||
discard # unreachable
|
||||
|
||||
tkBang.genRule(unary, nop, pcNone)
|
||||
|
||||
proc binary(comp: Compiler) =
|
||||
let opType = comp.previous.tokenType
|
||||
# safety checked in parsePrecedence
|
||||
let rule = opType.getRule.get
|
||||
comp.parsePrecedence(rule.applyRule.increment)
|
||||
|
||||
case opType:
|
||||
of tkPlus:
|
||||
comp.writeChunk(-1, opAdd)
|
||||
of tkMinus:
|
||||
comp.writeChunk(-1, opSubtract)
|
||||
of tkStar:
|
||||
comp.writeChunk(-1, opMultiply)
|
||||
of tkSlash:
|
||||
comp.writeChunk(-1, opDivide)
|
||||
of tkEqualEqual:
|
||||
comp.writeChunk(-1, opEqual)
|
||||
of tkBangEqual:
|
||||
comp.writeChunk(-1, opEqual)
|
||||
comp.writeChunk(0, opNot)
|
||||
of tkGreater:
|
||||
comp.writeChunk(-1, opGreater)
|
||||
of tkLess:
|
||||
comp.writeChunk(-1, opLess)
|
||||
of tkGreaterEqual:
|
||||
comp.writeChunk(-1, opLess)
|
||||
comp.writeChunk(0, opNot)
|
||||
of tkLessEqual:
|
||||
comp.writeChunk(-1, opGreater)
|
||||
comp.writeChunk(0, opNot)
|
||||
else:
|
||||
return # unreachable
|
||||
|
||||
tkMinus.genRule(unary, binary, pcTerm)
|
||||
tkPlus.genRule(nop, binary, pcTerm)
|
||||
tkSlash.genRule(nop, binary, pcFactor)
|
||||
tkStar.genRule(nop, binary, pcFactor)
|
||||
|
||||
tkEqualEqual.genRule(nop, binary, pcEquality)
|
||||
tkBangEqual.genRule(nop, binary, pcEquality)
|
||||
tkGreater.genRule(nop, binary, pcComparison)
|
||||
tkGreaterEqual.genRule(nop, binary, pcComparison)
|
||||
tkLess.genRule(nop, binary, pcComparison)
|
||||
tkLessEqual.genRule(nop, binary, pcComparison)
|
||||
|
||||
proc ifExpr(comp: Compiler) =
|
||||
# if expressions return the body if condition is truthy,
|
||||
# the else expression otherwise, unless there is no else:
|
||||
# if there is no else, it returns the condition if it is falsey
|
||||
comp.consume(tkLeftParen, "Expect '(' after 'if'.")
|
||||
comp.expression()
|
||||
comp.consume(tkRightParen, "Expect ')' after condition.")
|
||||
|
||||
let thenJump = comp.emitJump(0, opJumpIfFalse)
|
||||
|
||||
# conditional code that can be jumped over must leave the stack in tact!
|
||||
|
||||
comp.writeChunk(-1, opPop)
|
||||
comp.expression()
|
||||
# net change to stack: -1 + 1 = 0
|
||||
|
||||
let elseJump = comp.emitJump(0, opJump)
|
||||
comp.patchJump(thenJump)
|
||||
|
||||
if comp.match(tkElse):
|
||||
comp.writeChunk(-1, opPop)
|
||||
comp.expression()
|
||||
|
||||
comp.patchJump(elseJump)
|
||||
|
||||
|
||||
tkIf.genRule(ifExpr, nop, pcNone)
|
||||
|
||||
proc andExpr(comp: Compiler) =
|
||||
let endJump = comp.emitJump(0, opJumpIfFalse)
|
||||
|
||||
comp.writeChunk(-1, opPop)
|
||||
comp.parsePrecedence(pcAnd)
|
||||
# net effect on stack: -1 + 1 = 0
|
||||
|
||||
comp.patchJump(endJump)
|
||||
|
||||
tkAnd.genRule(nop, andExpr, pcAnd)
|
||||
|
||||
proc orExpr(comp: Compiler) =
|
||||
let elseJump = comp.emitJump(0, opJumpIfFalse)
|
||||
let endJump = comp.emitJump(0, opJump)
|
||||
|
||||
comp.patchJump(elseJump)
|
||||
|
||||
comp.writeChunk(-1, opPop)
|
||||
comp.parsePrecedence(pcOr)
|
||||
# net effect on stack: -1 + 1 = 0
|
||||
|
||||
comp.patchJump(endJump)
|
||||
|
||||
tkOr.genRule(nop, orExpr, pcOr)
|
||||
|
||||
proc debugExpr(comp: Compiler) =
|
||||
comp.expression()
|
||||
when debugCompiler:
|
||||
debugEcho &"debug expression, current stackindex: {comp.stackIndex}"
|
||||
comp.writeChunk(0, opPrint)
|
||||
|
||||
tkPrint.genRule(debugExpr, nop, pcNone)
|
||||
|
||||
proc parseWhile(comp: Compiler) =
|
||||
|
||||
comp.writeChunk(1, opNil) # return value
|
||||
let loopStart = comp.chunk.len
|
||||
comp.consume(tkLeftParen, "Expect '(' after 'while'.")
|
||||
# condition
|
||||
comp.expression()
|
||||
comp.consume(tkRightParen, "Expect ')' after condition.")
|
||||
|
||||
let exitJump = comp.emitJump(-1, opJumpIfFalsePop)
|
||||
# this cannot be handled with just opPop, since the net change in the
|
||||
# stack size inside code that is conditional must be 0!
|
||||
|
||||
# body
|
||||
comp.writeChunk(-1, opPop) # pop the old return value
|
||||
comp.expression()
|
||||
# net stack change: 1 + -1 = 0
|
||||
|
||||
comp.emitLoop(loopstart = loopStart, delta = 0, op = opLoop)
|
||||
comp.patchJump(exitJump)
|
||||
|
||||
|
||||
tkWhile.genRule(parseWhile, nop, pcNone)
|
||||
|
||||
proc parseFunct(comp: Compiler) =
|
||||
|
||||
# jump over
|
||||
let jumpOverBody = comp.emitJump(0, opJump)
|
||||
|
||||
comp.consume(tkLeftParen, "Expected '(' after keyword 'funct'.")
|
||||
|
||||
var params: seq[string]
|
||||
# parameters
|
||||
while comp.current.tokenType == tkIdentifier:
|
||||
comp.advance()
|
||||
params.add(comp.previous.text)
|
||||
if comp.current.tokenType == tkRightParen:
|
||||
break
|
||||
comp.consume(tkComma, "Expected ',' to separate items in the parameter list.")
|
||||
|
||||
comp.consume(tkRightParen, "Expected ')' after parameter list.")
|
||||
|
||||
# function body:
|
||||
let functII = comp.chunk.len
|
||||
comp.beginScope(function = true) # this saves the old stackindex, sets it to 0, points ^ and ^function at index 0
|
||||
# assumption:
|
||||
# the caller will create the following stack for the function to run in:
|
||||
# [0] = return value placeholder
|
||||
# [1] = arg #1
|
||||
# [2] = arg #2
|
||||
# [3] = arg #3
|
||||
|
||||
for i in countup(1, params.len):
|
||||
comp.stackIndex = i
|
||||
comp.addLocal(params[i-1], 0)
|
||||
comp.expression()
|
||||
when assertionsCompiler:
|
||||
let shouldbeStackIndex = params.len + 1
|
||||
if shouldbeStackIndex != comp.stackIndex:
|
||||
comp.error(&"Assertion failed: wrong stackindex ({comp.stackIndex}) in function declaration (should be {shouldbeStackIndex}).")
|
||||
comp.endScope()
|
||||
dec comp.stackIndex # the previous end scope did not put anything on the stack, it is jumped over
|
||||
|
||||
# get konvalue functions:
|
||||
let konFunct = newKonFunction(functII, params.len)
|
||||
|
||||
# end of function declaration:
|
||||
comp.patchJump(jumpOverBody)
|
||||
# put the fn object on the stack
|
||||
comp.writeConstant(konFunct)
|
||||
|
||||
tkFunct.genRule(parseFunct, nop, pcNone)
|
||||
|
||||
|
||||
# below are the expressions that can contain statements in some way
|
||||
# the only expressions that can contain a statement are:
|
||||
# the block expression
|
||||
proc statement(comp: Compiler)
|
||||
|
||||
proc parseBlock(comp: Compiler) =
|
||||
## Despite the name, can be used for statements if the arg statement is true
|
||||
## Also can be used for function bodies
|
||||
comp.beginScope()
|
||||
while comp.current.tokenType != tkRightBrace and comp.current.tokenType != tkEof:
|
||||
comp.statement()
|
||||
comp.endScope()
|
||||
|
||||
comp.consume(tkRightBrace, "Expect '}' after block.")
|
||||
|
||||
tkLeftBrace.genRule(parseBlock, nop, pcNone)
|
||||
|
||||
# statements
|
||||
|
||||
proc parseVariable(comp: Compiler, msg: string): int =
|
||||
## Parses variable declarations
|
||||
## During manipulation with variables:
|
||||
## if global:
|
||||
## consume the identifier and return index to work with
|
||||
## if local:
|
||||
## register the name with the vm
|
||||
comp.consume(tkIdentifier, msg)
|
||||
let name = comp.previous.text
|
||||
|
||||
if name[0] in {'^'}:
|
||||
comp.error("Illegal variable name.")
|
||||
|
||||
if comp.scopes.len > 0: # declareVariable
|
||||
# local
|
||||
|
||||
# check if name exists already within scope
|
||||
for i in countdown(comp.locals.high, 0):
|
||||
let local = comp.locals[i]
|
||||
if local.depth != -1 and local.depth < comp.scopes.len:
|
||||
break
|
||||
|
||||
if name == local.name:
|
||||
comp.error("Already a variable with this name in this scope.")
|
||||
break
|
||||
|
||||
comp.addLocal(name, 1)
|
||||
0 # index to the constant is irrelevant if the var is local
|
||||
else:
|
||||
# global
|
||||
comp.chunk.addConstant(name.toKonValue())
|
||||
|
||||
proc defineVariable(comp: Compiler, index: int) =
|
||||
## Generate code that moves the variable on the stack
|
||||
## to a variable at the right place in memory
|
||||
## the right place is defined by the 3 following byte after the op
|
||||
## the thing to move is the item below it
|
||||
|
||||
if comp.scopes.len > 0:
|
||||
# local variable: it's already on the right place
|
||||
# but we need to mark initialized
|
||||
comp.markInitialized()
|
||||
else:
|
||||
comp.writeChunk(-1, opDefineGlobal)
|
||||
comp.writeChunk(0, index.toDU8)
|
||||
|
||||
proc varStatement(comp: Compiler) =
|
||||
let globalIndex = comp.parseVariable("Expect variable name.")
|
||||
|
||||
if comp.match(tkEqual):
|
||||
comp.expression()
|
||||
else:
|
||||
comp.writeChunk(1, opNil)
|
||||
|
||||
comp.defineVariable(globalIndex)
|
||||
|
||||
|
||||
proc breakStatement(comp: Compiler) =
|
||||
if not comp.match(tkLabel):
|
||||
comp.error("Label expected after break.")
|
||||
|
||||
let label = comp.previous.text[1..^1]
|
||||
for i in countdown(comp.scopes.high, 0):
|
||||
let scope = comp.scopes[i]
|
||||
if scope.labels.contains(label):
|
||||
comp.jumpToEnd(scope)
|
||||
break
|
||||
|
||||
comp.consume(tkSemicolon, "Semicolon expected after break statement.")
|
||||
if comp.current.tokenType != tkRightBrace:
|
||||
comp.error("Break statement must be the last element inside the innermost block it is in.")
|
||||
|
||||
proc statement(comp: Compiler) =
|
||||
if comp.match(tkVar):
|
||||
comp.varStatement()
|
||||
comp.consume(tkSemicolon, "Semicolon expected after expression statement.")
|
||||
elif comp.match(tkBreak):
|
||||
comp.breakStatement()
|
||||
else:
|
||||
comp.expression()
|
||||
comp.writeChunk(-1, opPop)
|
||||
comp.consume(tkSemicolon, "Semicolon expected after expression statement.")
|
||||
|
||||
if comp.panicMode:
|
||||
comp.synchronize()
|
||||
|
||||
proc compile*(comp: Compiler) =
|
||||
comp.scanner = newScanner(comp.source)
|
||||
comp.writeChunk(0, opNil)
|
||||
# the starting stackIndex is 0, which points to this nil
|
||||
# it is correctly set to delta = 0!!!
|
||||
comp.advance()
|
||||
while comp.current.tokenType != tkEof:
|
||||
comp.statement()
|
||||
comp.writeChunk(-1, opPop)
|
||||
comp.writeChunk(0, opReturn)
|
||||
when debugDumpChunk:
|
||||
if not comp.hadError:
|
||||
comp.chunk.disassembleChunk()
|
||||
|
|
@ -0,0 +1,32 @@
|
|||
type
|
||||
LineEditorChoice = enum
|
||||
leBasic, leRdstdin
|
||||
ReadlineInterruptedException* = object of CatchableError
|
||||
|
||||
# choose debug options here
|
||||
const debugVM* = false
|
||||
const debugScanner* = false
|
||||
const debugCompiler* = false
|
||||
const debugDumpChunk* = false
|
||||
const assertionsVM* = false # sanity checks in the VM, such as the stack being empty at the end
|
||||
const assertionsCompiler* = false # sanity checks in the compiler
|
||||
const profileInstructions* = false # if true, the time spent on every opcode is measured
|
||||
|
||||
# choose a line editor for the repl
|
||||
const lineEditor = leRdstdin
|
||||
|
||||
when lineEditor == leRdstdin:
|
||||
import rdstdin
|
||||
|
||||
proc konLineEditor*: string =
|
||||
proc ctrlc =
|
||||
raise newException(ReadlineInterruptedException, "Ctrl+C/D pressed.")
|
||||
when lineEditor == leBasic:
|
||||
write stdout, "\r-> "
|
||||
result = stdin.readLine()
|
||||
when lineEditor == leRdstdin:
|
||||
var line: string
|
||||
let ok = readLineFromStdin("-> ", line)
|
||||
if not ok:
|
||||
ctrlc()
|
||||
return line
|
||||
|
|
@ -0,0 +1,52 @@
|
|||
import vm
|
||||
import compiler
|
||||
import os
|
||||
import config
|
||||
|
||||
type Result = enum
|
||||
rsOK, rsCompileError, rsRuntimeError
|
||||
|
||||
proc interpret(name: string, source: string): Result =
|
||||
let compiler = newCompiler(name, source)
|
||||
compiler.compile()
|
||||
if compiler.hadError:
|
||||
return rsCompileError
|
||||
let vm = newVM(compiler.chunk)
|
||||
case vm.run():
|
||||
of irOK:
|
||||
rsOK
|
||||
of irRuntimeError:
|
||||
rsRuntimeError
|
||||
|
||||
|
||||
proc repl =
|
||||
while true:
|
||||
try:
|
||||
let line = konLineEditor()
|
||||
if line.len > 0:
|
||||
discard interpret("repl", line)
|
||||
except ReadlineInterruptedException:
|
||||
break
|
||||
|
||||
proc runFile(path: string) =
|
||||
case interpret(path, readFile(path)):
|
||||
of rsCompileError:
|
||||
quit 65
|
||||
of rsRuntimeError:
|
||||
quit 70
|
||||
of rsOK:
|
||||
quit 0
|
||||
|
||||
const hardcodedPath* = ""
|
||||
|
||||
if paramCount() == 0:
|
||||
if hardcodedPath == "":
|
||||
repl()
|
||||
else:
|
||||
runFile(hardcodedPath)
|
||||
elif paramCount() == 1:
|
||||
runFile(paramStr(1))
|
||||
else:
|
||||
echo "Maximum param count is 1"
|
||||
quit 1
|
||||
|
||||
|
|
@ -0,0 +1,9 @@
|
|||
|
||||
template padd*[T](x: ptr T, num: int): ptr T =
|
||||
cast[ptr T](cast[int](x) + num)
|
||||
|
||||
template psub*[T](x: ptr T, num: int): ptr T =
|
||||
cast[ptr T](cast[int](x) - num)
|
||||
|
||||
template pdiff*[T](x: ptr T, y: ptr): int =
|
||||
cast[int](x) - cast[int](y)
|
||||
|
|
@ -0,0 +1,200 @@
|
|||
import strutils
|
||||
import tables
|
||||
import strformat
|
||||
|
||||
type
|
||||
Scanner* = ref object
|
||||
start: int
|
||||
current: int
|
||||
line: int
|
||||
source: string
|
||||
|
||||
TokenType* = enum
|
||||
tkNone, # the default tokentype, if encountered anywhere, erroring out is the best course of action
|
||||
tkLeftParen, tkRightParen, tkLeftBrace, tkRightBrace, tkComma, tkDot,
|
||||
tkMinus, tkPlus, tkSemicolon, tkSlash, tkStar, tkBang, tkBangEqual,
|
||||
tkGreater, tkGreaterEqual, tkLess, tkLessEqual, tkEqual, tkEqualEqual,
|
||||
tkIdentifier, tkString,
|
||||
tkNumber, tkAnd, tkElse, tkFalse, tkFor, tkFunct, tkGoto, tkIf, tkNil,
|
||||
tkOr, tkPrint, tkLabel, tkBreak, tkTrue, tkVar, tkWhile,
|
||||
tkError, tkEof
|
||||
|
||||
Token* = object
|
||||
tokenType*: TokenType
|
||||
text*: string
|
||||
line*: int
|
||||
|
||||
proc debugPrint*(token: Token) =
|
||||
write stdout, &"Token of type {$token.tokenType} [{token.text}] at line {$token.line}\n"
|
||||
|
||||
proc isAtEnd(scanner: Scanner): bool =
|
||||
scanner.current > scanner.source.high
|
||||
|
||||
proc advance(scanner: Scanner): char =
|
||||
scanner.current.inc
|
||||
scanner.source[scanner.current - 1]
|
||||
|
||||
proc peek(scanner: Scanner): char =
|
||||
if scanner.isAtEnd():
|
||||
'\0'
|
||||
else:
|
||||
scanner.source[scanner.current]
|
||||
|
||||
proc peekNext(scanner: Scanner): char =
|
||||
if scanner.current < scanner.source.high:
|
||||
scanner.source[scanner.current + 1]
|
||||
else:
|
||||
'\0'
|
||||
|
||||
proc match(scanner: Scanner, exp: char): bool =
|
||||
if scanner.peek() == exp:
|
||||
discard scanner.advance()
|
||||
true
|
||||
else:
|
||||
false
|
||||
|
||||
proc newScanner*(source: string): Scanner =
|
||||
Scanner(source: source, line: 0, current: 0)
|
||||
|
||||
proc makeToken(scanner: Scanner, tokenType: TokenType): Token =
|
||||
result.tokenType = tokenType
|
||||
result.text = scanner.source[scanner.start..scanner.current-1]
|
||||
result.line = scanner.line
|
||||
|
||||
proc errorToken(scanner: Scanner, msg: string): Token =
|
||||
result.tokenType = tkError
|
||||
result.text = msg
|
||||
result.line = scanner.line
|
||||
|
||||
proc skipWhitespace(scanner: Scanner) =
|
||||
while true:
|
||||
let c = scanner.peek()
|
||||
case c:
|
||||
of {' ', '\r', '\t'}:
|
||||
discard scanner.advance()
|
||||
of '\n':
|
||||
scanner.line.inc
|
||||
discard scanner.advance()
|
||||
of '/':
|
||||
if scanner.peekNext() == '/':
|
||||
while scanner.peek != '\n' and not scanner.isAtEnd():
|
||||
discard scanner.advance()
|
||||
else:
|
||||
return
|
||||
else:
|
||||
return
|
||||
|
||||
proc scanString(scanner: Scanner): Token =
|
||||
while scanner.peek() != '\"' and not scanner.isAtEnd():
|
||||
if scanner.peek() == '\n':
|
||||
scanner.line.inc
|
||||
discard scanner.advance()
|
||||
|
||||
if scanner.isAtEnd():
|
||||
return scanner.errorToken("Unterminated string.")
|
||||
|
||||
discard scanner.advance()
|
||||
scanner.makeToken(tkString)
|
||||
|
||||
proc scanNumber(scanner: Scanner): Token =
|
||||
while scanner.peek() in Digits:
|
||||
discard scanner.advance()
|
||||
|
||||
if scanner.peek() == '.' and scanner.peekNext() in Digits:
|
||||
discard scanner.advance()
|
||||
while scanner.peek() in Digits:
|
||||
discard scanner.advance()
|
||||
|
||||
return scanner.makeToken(tkNumber)
|
||||
|
||||
const keywords = {
|
||||
"and": tkAnd,
|
||||
"break": tkBreak,
|
||||
"else": tkElse,
|
||||
"false": tkFalse,
|
||||
"for": tkFor,
|
||||
"funct": tkFunct,
|
||||
# here's a language that uses funct... still waiting for the day when a good de-funct joke comes to my mind that I can abuse
|
||||
"goto": tkGoto,
|
||||
"if": tkIf,
|
||||
"nil": tkNil,
|
||||
"or": tkOr,
|
||||
"print": tkPrint,
|
||||
"true": tkTrue,
|
||||
"var": tkVar,
|
||||
"while": tkWhile
|
||||
}.toTable
|
||||
|
||||
proc canStartIdent(chr: char): bool =
|
||||
chr in Letters or chr in {'_', '^'}
|
||||
|
||||
proc canContIdent(chr: char): bool =
|
||||
canStartIdent(chr) or chr in Digits
|
||||
|
||||
proc scanIdentifier(scanner: Scanner): Token =
|
||||
while scanner.peek.canContIdent:
|
||||
discard scanner.advance()
|
||||
|
||||
let text = scanner.source[scanner.start..scanner.current-1]
|
||||
|
||||
if keywords.hasKey(text):
|
||||
return scanner.makeToken(keywords[text])
|
||||
|
||||
return scanner.makeToken(tkIdentifier)
|
||||
|
||||
proc canContLabel(chr: char): bool =
|
||||
chr in Letters or chr == '_'
|
||||
|
||||
proc scanLabel(scanner: Scanner): Token =
|
||||
if not scanner.peek.canContLabel:
|
||||
return scanner.errorToken("Labels must only contain letters and underscores.")
|
||||
|
||||
while scanner.peek.canContLabel:
|
||||
discard scanner.advance()
|
||||
|
||||
return scanner.makeToken(tkLabel)
|
||||
|
||||
proc scanToken*(scanner: Scanner): Token =
|
||||
|
||||
scanner.skipWhitespace()
|
||||
scanner.start = scanner.current
|
||||
|
||||
if scanner.isAtEnd():
|
||||
return scanner.makeToken(tkEof)
|
||||
|
||||
let c = scanner.advance()
|
||||
|
||||
case c:
|
||||
of '(': return scanner.makeToken(tkLeftParen)
|
||||
of ')': return scanner.makeToken(tkRightParen)
|
||||
of '{': return scanner.makeToken(tkLeftBrace)
|
||||
of '}': return scanner.makeToken(tkRightBrace)
|
||||
of ';': return scanner.makeToken(tkSemicolon)
|
||||
of ',': return scanner.makeToken(tkComma)
|
||||
of '.': return scanner.makeToken(tkDot)
|
||||
of '-': return scanner.makeToken(tkMinus)
|
||||
of '+': return scanner.makeToken(tkPlus)
|
||||
of '/': return scanner.makeToken(tkSlash)
|
||||
of '*': return scanner.makeToken(tkStar)
|
||||
of '!':
|
||||
return if scanner.match('='): scanner.makeToken(tkBangEqual) else: scanner.makeToken(tkBang)
|
||||
|
||||
of '=':
|
||||
return if scanner.match('='): scanner.makeToken(tkEqualEqual) else: scanner.makeToken(tkEqual)
|
||||
|
||||
of '<':
|
||||
return if scanner.match('='): scanner.makeToken(tkLessEqual) else: scanner.makeToken(tkLess)
|
||||
|
||||
of '>':
|
||||
return if scanner.match('='): scanner.makeToken(tkGreaterEqual) else: scanner.makeToken(tkGreater)
|
||||
of '\"':
|
||||
return scanner.scanString()
|
||||
of Digits:
|
||||
return scanner.scanNumber()
|
||||
of '@':
|
||||
return scanner.scanLabel()
|
||||
else:
|
||||
if c.canStartIdent():
|
||||
return scanner.scanIdentifier()
|
||||
else:
|
||||
return scanner.errorToken("Unexpected character.")
|
||||
|
|
@ -0,0 +1,22 @@
|
|||
import ../scanner
|
||||
import ../chunk
|
||||
import ../config
|
||||
|
||||
import parser/parser
|
||||
import emitter/emitter
|
||||
|
||||
proc compile*(source: string): CompileResult =
|
||||
result = CompileResult(ok: false)
|
||||
let scanner = newScanner(source)
|
||||
let parser = newParser(scanner)
|
||||
let nodeRoot = parser.parse()
|
||||
if parser.hadError:
|
||||
return result
|
||||
let emitter = newEmitter(nodeRoot)
|
||||
let chunk = emitter.emit()
|
||||
if emitter.hadError:
|
||||
return result
|
||||
when debugDumpChunk:
|
||||
if not emitter.hadError:
|
||||
chunk.disassembleChunk()
|
||||
return CompileResult(ok: true, chunk: chunk)
|
||||
|
|
@ -0,0 +1,14 @@
|
|||
import ../types
|
||||
import ../../scanner
|
||||
|
||||
import utils
|
||||
import statements
|
||||
|
||||
proc newParser*(sc: Scanner): Parser =
|
||||
result.new()
|
||||
result.scanner = sc
|
||||
|
||||
proc parse*(par: Parser): Node =
|
||||
result = Node(kind: nkRoot)
|
||||
while par.current.tokenType != tkEof:
|
||||
result.children.add(par.statement())
|
||||
|
|
@ -0,0 +1,45 @@
|
|||
import ../types
|
||||
import utils
|
||||
|
||||
# below are the expressions that can contain statements in some way
|
||||
# the only expressions that can contain a statement are:
|
||||
# the block expression
|
||||
proc statement*(par: Parser)
|
||||
|
||||
proc parseBlock(par: Parser): Node =
|
||||
## Despite the name, can be used for statements if the arg statement is true
|
||||
## Also can be used for function bodies
|
||||
result = Node(kind: nkBlockExpr)
|
||||
while par.current.tokenType != tkRightBrace and par.current.tokenType != tkEof:
|
||||
result.children.add(par.statement())
|
||||
|
||||
par.consume(tkRightBrace, "Expect '}' after block.")
|
||||
|
||||
# statements
|
||||
|
||||
proc breakStatement(par: Parser): Node =
|
||||
if not par.match(tkLabel):
|
||||
par.error("Label expected after break.")
|
||||
|
||||
let label = comp.previous.text[1..^1]
|
||||
result = Node(kind: nkBreak, label: label)
|
||||
|
||||
par.consume(tkSemicolon, "Semicolon expected after break statement.")
|
||||
if par.current.tokenType != tkRightBrace:
|
||||
par.error("Break statement must be the last element inside the innermost block it is in.")
|
||||
|
||||
proc statement*(par: Parser): Node =
|
||||
if par.match(tkVar):
|
||||
result = par.varStatement()
|
||||
par.consume(tkSemicolon, "Semicolon expected after expression statement.")
|
||||
elif par.match(tkDef):
|
||||
result = par.procStatement()
|
||||
par.consume(tkSemicolon, "Semicolon expected after procedure declaration.")
|
||||
elif par.match(tkBreak):
|
||||
result = par.breakStatement()
|
||||
else:
|
||||
result = Node(kind: nkExprStmt, expression: par.expression())
|
||||
par.consume(tkSemicolon, "Semicolon expected after expression statement.")
|
||||
|
||||
if par.panicMode:
|
||||
par.synchronize()
|
||||
|
|
@ -0,0 +1,52 @@
|
|||
import ../types
|
||||
import ../../config
|
||||
|
||||
proc errorAt*(par: Parser, line: int, msg: string, at: string = "") =
|
||||
if par.panicMode:
|
||||
return
|
||||
write stderr, &"[line {line}] Error "
|
||||
if at.len > 0:
|
||||
write stderr, &"at {at} "
|
||||
write stderr, msg
|
||||
write stderr, "\n"
|
||||
par.hadError = true
|
||||
par.panicMode = true
|
||||
|
||||
proc error*(par: Parser, msg: string) =
|
||||
## create a simple error message
|
||||
par.errorAt(par.previous.line, msg, par.previous.text)
|
||||
|
||||
proc errorAtCurrent*(par: Parser, msg: string, supress: bool = false) =
|
||||
par.errorAt(par.current.line, msg, if supress: "" else: par.current.text)
|
||||
|
||||
proc advance*(par: Parser) =
|
||||
par.previous = par.current
|
||||
while true:
|
||||
par.current = par.scanner.scanToken()
|
||||
when debugScanner:
|
||||
par.current.debugPrint()
|
||||
if (par.current.tokenType != tkError):
|
||||
break
|
||||
par.errorAtCurrent(par.current.text, true)
|
||||
|
||||
proc match*(par: Parser, tokenType: TokenType): bool =
|
||||
if par.current.tokenType == tokenType:
|
||||
par.advance()
|
||||
true
|
||||
else:
|
||||
false
|
||||
|
||||
proc consume*(par: Parser, tokenType: TokenType, msg: string) =
|
||||
if par.current.tokenType == tokenType:
|
||||
par.advance()
|
||||
else:
|
||||
par.errorAtCurrent(msg)
|
||||
|
||||
proc synchronize*(par: Parser) =
|
||||
par.panicMode = false
|
||||
while par.current.tokenType != tkEof:
|
||||
if par.previous.tokenType in {tkSemicolon, tkRightBrace}:
|
||||
return
|
||||
if par.current.tokenType in {tkFunct, tkVar, tkFor, tkIf, tkWhile}:
|
||||
return
|
||||
par.advance()
|
||||
|
|
@ -0,0 +1,35 @@
|
|||
import ../scanner
|
||||
import ../chunk
|
||||
import ../types/value
|
||||
|
||||
type
|
||||
Parser* = ref object
|
||||
scanner*: Scanner
|
||||
current*: Token
|
||||
previous*: Token
|
||||
hadError*: bool
|
||||
panicMode*: bool
|
||||
|
||||
NodeKind* = enum
|
||||
nkBlockExpr, nkRoot,
|
||||
nkExprStmt,
|
||||
nkBreak,
|
||||
nkConst
|
||||
|
||||
Node* = ref object
|
||||
case kind*: NodeKind:
|
||||
of nkBlockExpr, nkRoot:
|
||||
children*: seq[Node]
|
||||
of nkExprStmt:
|
||||
expression*: Node
|
||||
of nkBreak:
|
||||
label*: string
|
||||
of nkConst:
|
||||
constant*: NdValue
|
||||
|
||||
CompileResult* = object
|
||||
case ok*: bool:
|
||||
of true:
|
||||
chunk*: Chunk
|
||||
of false:
|
||||
discard
|
||||
|
|
@ -0,0 +1,142 @@
|
|||
import strformat
|
||||
|
||||
type
|
||||
KonType* = enum
|
||||
ktNil, ktBool, ktFloat, ktString,
|
||||
ktFunct,
|
||||
ktTypeError,
|
||||
|
||||
const errorTypes = {ktTypeError}
|
||||
|
||||
type
|
||||
KonValue* = object
|
||||
case konType*: KonType:
|
||||
of ktNil:
|
||||
discard
|
||||
of ktBool:
|
||||
boolValue*: bool
|
||||
of ktFloat:
|
||||
floatValue*: float64
|
||||
of ktString:
|
||||
stringValue*: string
|
||||
of ktFunct:
|
||||
module*: string
|
||||
entryII*: int # entry instruction index
|
||||
arity*: int # number of arguments
|
||||
of errorTypes:
|
||||
message*: string
|
||||
|
||||
# KON VALUE HELPERS, MUST BE DEFINED FOR EVERY KONVALUE
|
||||
|
||||
proc `$`*(val: KonValue): string =
|
||||
case val.konType:
|
||||
of ktFloat:
|
||||
return $val.floatValue
|
||||
of ktBool:
|
||||
return $val.boolValue
|
||||
of ktNil:
|
||||
return "nil"
|
||||
of ktString:
|
||||
return val.stringValue
|
||||
of ktFunct:
|
||||
return &"Function object: {val.entryII}"
|
||||
of errorTypes:
|
||||
let ename = $val.konType
|
||||
return &"{ename[2..^1]}: {val.message}"
|
||||
|
||||
proc isError*(val: KonValue): bool =
|
||||
val.konType in errorTypes
|
||||
|
||||
proc isFalsey*(val: KonValue): bool =
|
||||
val.konType in {ktNil} or (val.konType == ktBool and not val.boolValue)
|
||||
|
||||
template isTruthy*(val: KonValue): bool =
|
||||
not isFalsey(val)
|
||||
|
||||
proc equal*(val, right: KonValue): bool =
|
||||
if val.konType != right.konType:
|
||||
false
|
||||
else:
|
||||
case val.konType:
|
||||
of ktFloat:
|
||||
val.floatValue == right.floatValue
|
||||
of ktBool:
|
||||
val.boolValue == right.boolValue
|
||||
of ktNil:
|
||||
true
|
||||
of ktString:
|
||||
val.stringValue == right.stringValue
|
||||
of ktFunct:
|
||||
val.entryII == right.entryII
|
||||
# same entry II/module but diff arity is a bug
|
||||
of errorTypes:
|
||||
false # error comparison is undefined
|
||||
|
||||
# NIM VALUE TO KON VALUE WRAPPERS
|
||||
|
||||
proc toKonValue*(val: float): KonValue =
|
||||
KonValue(konType: ktFloat, floatValue: val)
|
||||
|
||||
proc toKonValue*(val: bool): KonValue =
|
||||
KonValue(konType: ktBool, boolValue: val)
|
||||
|
||||
proc toKonValue*(val: string): KonValue =
|
||||
KonValue(konType: ktString, stringValue: val)
|
||||
|
||||
proc newKonFunction*(ii: int, arity: int): KonValue =
|
||||
KonValue(konType: ktFunct, entryII: ii, arity: arity)
|
||||
|
||||
proc toKonValue*: KonValue =
|
||||
KonValue(konType: ktNil)
|
||||
|
||||
proc konTypeError*(msg: string): KonValue =
|
||||
KonValue(konType: ktTypeError, message: msg)
|
||||
|
||||
# OPERATIONS
|
||||
# NOTE: these operations can return ktTypeError with a message if types are invalid
|
||||
|
||||
proc negate*(val: KonValue): KonValue =
|
||||
if (val.konType != ktFloat):
|
||||
return konTypeError("Operand must be a number.")
|
||||
else:
|
||||
return toKonValue(-val.floatValue)
|
||||
|
||||
proc add*(val: KonValue, right: KonValue): KonValue =
|
||||
if val.konType == ktFloat and right.konType == ktFloat:
|
||||
return toKonValue(val.floatValue + right.floatValue)
|
||||
elif val.konType == ktString and right.konType == ktString:
|
||||
return toKonValue(val.stringValue & right.stringValue)
|
||||
else:
|
||||
return konTypeError(&"Attempt to add types {val.konType} and {right.konType}.")
|
||||
|
||||
proc subtract*(val: KonValue, right: KonValue): KonValue =
|
||||
if val.konType == ktFloat and right.konType == ktFloat:
|
||||
return toKonValue(val.floatValue - right.floatValue)
|
||||
else:
|
||||
return konTypeError(&"Attempt to subtract types {val.konType} and {right.konType}.")
|
||||
|
||||
proc multiply*(val: KonValue, right: KonValue): KonValue =
|
||||
if val.konType == ktFloat and right.konType == ktFloat:
|
||||
return toKonValue(val.floatValue * right.floatValue)
|
||||
else:
|
||||
return konTypeError(&"Attempt to multiply types {val.konType} and {right.konType}.")
|
||||
|
||||
|
||||
proc divide*(val: KonValue, right: KonValue): KonValue =
|
||||
if val.konType == ktFloat and right.konType == ktFloat:
|
||||
return toKonValue(val.floatValue / right.floatValue)
|
||||
else:
|
||||
return konTypeError(&"Attempt to divide types {val.konType} and {right.konType}.")
|
||||
|
||||
proc `<`*(val: KonValue, right: KonValue): KonValue =
|
||||
if val.konType == ktFloat and right.konType == ktFloat:
|
||||
return toKonValue(val.floatValue < right.floatValue)
|
||||
else:
|
||||
return konTypeError(&"Attempt to compare types {val.konType} and {right.konType}.")
|
||||
|
||||
|
||||
proc `>`*(val: KonValue, right: KonValue): KonValue =
|
||||
if val.konType == ktFloat and right.konType == ktFloat:
|
||||
return toKonValue(val.floatValue > right.floatValue)
|
||||
else:
|
||||
return konTypeError(&"Attempt to compare types {val.konType} and {right.konType}.")
|
||||
|
|
@ -0,0 +1,236 @@
|
|||
import strformat
|
||||
import tables
|
||||
|
||||
import value
|
||||
import chunk
|
||||
import config
|
||||
import pointerutils
|
||||
when profileInstructions:
|
||||
import times
|
||||
import std/monotimes
|
||||
|
||||
type
|
||||
Frame = object
|
||||
stackBottom: int # the absolute index of where 0 inside the frame is
|
||||
returnIp: ptr uint8
|
||||
|
||||
VM* = ref object
|
||||
chunk: Chunk
|
||||
ip: ptr uint8
|
||||
stack: seq[KonValue]
|
||||
hadError: bool
|
||||
globals: Table[string, KonValue]
|
||||
frames: seq[Frame]
|
||||
|
||||
InterpretResult* = enum
|
||||
irOK, irRuntimeError
|
||||
|
||||
|
||||
proc newVM*(ch: Chunk): VM =
|
||||
result = VM(chunk: ch, stack: newSeqOfCap[KonValue](256), frames: newSeqOfCap[Frame](4))
|
||||
result.ip = ch.code[0].unsafeAddr
|
||||
|
||||
proc push(vm: VM, val: KonValue) =
|
||||
vm.stack.add(val)
|
||||
|
||||
proc pop(vm: VM): KonValue =
|
||||
vm.stack.pop()
|
||||
|
||||
proc peek(vm: VM): KonValue =
|
||||
vm.stack[vm.stack.high]
|
||||
|
||||
proc runtimeError(vm: VM, msg: string) =
|
||||
let ii = vm.ip.pdiff(vm.chunk.code[0].unsafeAddr)
|
||||
let line = vm.chunk.lines[ii]
|
||||
write stderr, &"[line: {line}] {msg}\n"
|
||||
vm.hadError = true
|
||||
|
||||
proc pushSafe(vm: VM, val: KonValue): bool =
|
||||
## returns if the value is not a runtime error
|
||||
## prints the error if it is a runtime error
|
||||
## pushes it to the stack if it is not an error
|
||||
if val.isError():
|
||||
vm.runtimeError($val)
|
||||
return false
|
||||
else:
|
||||
vm.push(val)
|
||||
return true
|
||||
|
||||
proc advance(vm: VM): uint8 =
|
||||
result = vm.ip[]
|
||||
vm.ip = vm.ip.padd(1)
|
||||
|
||||
proc readDU8(vm: VM): int =
|
||||
result = vm.ip.DU8ptrToInt
|
||||
vm.ip = vm.ip.padd(argSize)
|
||||
|
||||
proc readConstant(vm: VM): KonValue =
|
||||
let index = vm.readDU8()
|
||||
vm.chunk.constants[index]
|
||||
|
||||
proc binary(op: OpCode, left: KonValue, right: KonValue): KonValue =
|
||||
case op:
|
||||
of opAdd:
|
||||
return left.add(right)
|
||||
of opSubtract:
|
||||
return left.subtract(right)
|
||||
of opMultiply:
|
||||
return left.multiply(right)
|
||||
of opDivide:
|
||||
return left.divide(right)
|
||||
else:
|
||||
discard #unreachable
|
||||
|
||||
when profileInstructions:
|
||||
# not a perfect profiling approach, doing random stacktrace dumps
|
||||
# x amount of times per second to get the current source line
|
||||
# would be better
|
||||
var durations: array[OpCode, Duration]
|
||||
|
||||
proc run*(vm: VM): InterpretResult =
|
||||
|
||||
template frameBottom: int = vm.frames[vm.frames.high].stackBottom
|
||||
while true:
|
||||
{.computedgoto.} # See https://nim-lang.org/docs/manual.html#pragmas-computedgoto-pragma
|
||||
|
||||
let ins = vm.advance.OpCode
|
||||
|
||||
when debugVM:
|
||||
let opname = ($ins)
|
||||
var msg = &"[{vm.ii:4}] {opname}"
|
||||
msg &= " Stack: [ "
|
||||
for i in 0 .. vm.stack.high:
|
||||
let e = vm.stack[i]
|
||||
if i == frameBottom:
|
||||
msg &= &"<{e}> "
|
||||
else:
|
||||
msg &= &"{e} "
|
||||
msg &= "]"
|
||||
echo msg
|
||||
|
||||
when profileInstructions:
|
||||
let startTime = getMonoTime()
|
||||
|
||||
case ins:
|
||||
of opPop:
|
||||
discard vm.pop()
|
||||
of opConstant:
|
||||
let val: KonValue = vm.readConstant()
|
||||
vm.push(val)
|
||||
of opNegate:
|
||||
let val = vm.pop.negate
|
||||
if not vm.pushSafe(val):
|
||||
break
|
||||
of opAdd, opSubtract, opMultiply, opDivide:
|
||||
let right = vm.pop()
|
||||
let left = vm.pop()
|
||||
if not vm.pushSafe(binary(ins, left, right)):
|
||||
break
|
||||
of opReturn:
|
||||
if vm.frames.len == 0:
|
||||
break
|
||||
else:
|
||||
vm.ip = vm.frames.pop().returnIp # remove frame that's over
|
||||
of opTrue:
|
||||
vm.push(toKonValue(true))
|
||||
of opFalse:
|
||||
vm.push(toKonValue(false))
|
||||
of opNil:
|
||||
vm.push(toKonValue())
|
||||
of opNot:
|
||||
vm.push(toKonValue(vm.pop.isFalsey))
|
||||
of opEqual:
|
||||
vm.push(toKonValue(vm.pop.equal(vm.pop())))
|
||||
of opLess:
|
||||
if not vm.pushSafe(vm.pop() > vm.pop()):
|
||||
break
|
||||
of opGreater:
|
||||
if not vm.pushSafe(vm.pop() < vm.pop()):
|
||||
break
|
||||
of opPrint:
|
||||
echo $vm.peek()
|
||||
of opDefineGlobal:
|
||||
let name = vm.readConstant().stringValue
|
||||
if not vm.globals.hasKey(name):
|
||||
vm.globals[name] = vm.pop()
|
||||
else:
|
||||
vm.runtimeError("Attempt to redefine an existing global variable.")
|
||||
break
|
||||
of opGetGlobal:
|
||||
let name = vm.readConstant().stringValue
|
||||
if vm.globals.hasKey(name):
|
||||
vm.push(vm.globals[name])
|
||||
else:
|
||||
vm.runtimeError(&"Undefined global variable {name}.")
|
||||
break
|
||||
of opSetGlobal:
|
||||
let name = vm.readConstant().stringValue
|
||||
if vm.globals.hasKey(name):
|
||||
vm.globals[name] = vm.peek()
|
||||
else:
|
||||
vm.runtimeError(&"Attempt to set undefined global variable {name}.")
|
||||
break
|
||||
of opGetLocal:
|
||||
let slot = vm.readDU8()
|
||||
vm.push(vm.stack[slot + frameBottom])
|
||||
of opSetLocal:
|
||||
let slot = vm.readDU8()
|
||||
vm.stack[slot + frameBottom] = vm.peek()
|
||||
of opJumpIfFalse:
|
||||
let offset = vm.readDU8()
|
||||
if vm.peek.isFalsey:
|
||||
vm.ip = vm.ip.padd(offset)
|
||||
of opJumpIfFalsePop:
|
||||
let offset = vm.readDU8()
|
||||
if vm.pop.isFalsey:
|
||||
vm.ip = vm.ip.padd(offset)
|
||||
of opJump:
|
||||
let offset = vm.readDU8()
|
||||
vm.ip = vm.ip.padd(offset)
|
||||
of opLoop:
|
||||
let offset = vm.readDU8()
|
||||
vm.ip = vm.ip.psub(offset)
|
||||
of opCall:
|
||||
# create the call env
|
||||
# current stack before opCall:
|
||||
# ... <funct obj> <arg1> <arg2> <arg3>
|
||||
# opCall converts it to this
|
||||
# ... <ret val> <arg1> <arg2> <arg3>
|
||||
let argcount = vm.readDU8()
|
||||
let funct = vm.stack[vm.stack.high - argcount]
|
||||
if funct.konType != ktFunct:
|
||||
vm.runtimeError("Attempt to call a non-funct (a defunct?).") # here is a bad defunct joke
|
||||
break
|
||||
if funct.arity != argcount:
|
||||
vm.runtimeError(&"Wrong number of arguments, expected {funct.arity}, got {argcount}.")
|
||||
break
|
||||
# if funct.module ... TODO
|
||||
|
||||
vm.stack[vm.stack.high - argcount] = toKonValue() # replace the function with nil: this is the return value slot
|
||||
|
||||
# create new frame
|
||||
vm.frames.add(Frame(stackBottom: vm.stack.high - argcount, returnIp: vm.ip))
|
||||
|
||||
vm.ip = vm.chunk.code[0].unsafeAddr.padd(funct.entryII) # jump to the entry point
|
||||
|
||||
when profileInstructions:
|
||||
durations[ins] += getMonoTime() - startTime
|
||||
|
||||
when assertionsVM:
|
||||
if not vm.hadError and vm.stack.len > 0:
|
||||
vm.runtimeError(&"VM Assertion failed: stack is of non-zero length {vm.stack.len} after execution has finished.")
|
||||
|
||||
when profileInstructions:
|
||||
for op in OpCode:
|
||||
let dur = durations[op].inMilliseconds
|
||||
echo &"OpCode: {op} total duration {dur} ms"
|
||||
|
||||
if vm.hadError:
|
||||
irRuntimeError
|
||||
else:
|
||||
irOK
|
||||
|
||||
proc interpretChunk*(ch: Chunk): InterpretResult =
|
||||
let vm = newVM(ch)
|
||||
return vm.run()
|
||||
|
||||
Loading…
Reference in New Issue